Refrigeration



May 31, 1932.

J. G. BERGDOLL REFRIGERATION Filed July 21, 1928 3 Sheets-Sheqt l gwventoo I skew aw y 1932- J. G. BERGDO LL 1,350,447

REFRIGERATION I Filed July 21, 1928 3 Sheets-Sheet 2 m. csmimm 55 47 WATER 911T FLW wlcg. 2

WATER,

o 42 m FL w y 3 9 J. G. BERGDOLL 1,360,447

REFRIGERATION Filed July 21, 1928 3 Sheets-Sheet 3 WATER BUT-TLZW D f CQNPENJEK 55 57 Patented May 31, 1932 UNITED STATES PATENT orrlcs JOHN G. BERG-DOLL, OF YORK, PENNSYLVANIA, ASSIGNOB TO YORK ICE MACHINERY CORPORATION, OF YORK, PENNSYLVANIA, A CQBPORATION OF DELAWARE REFRIGERATION Application filed July 21, 1928. Serial No. 294,418.

This invention relates to refrigerating systems and particularly to means for operating the condenser under super-pressure when the refrigerant is discharged at or near the critical temperature.

While the invention is not limited to any particular refrigerant, but is useful with any refrigerant condensed within the temperature ranges just mentioned, it has particular commercial utility in connection with carhon-dioxide machines and will be discussed on the basis of the properties of carbondioxide. This discussion, however, is merely for illustrative purposes, and no necessary limitation to carbon-dioxide is implied except to the extent expressly stated.

To secure the best refrigerating efiect the lowest practicable temperature of the refrigerant leaving the condenser should always be obtained. Space is always a consideration, and where the temperature and amount of available cooling water are such as to enter as controlling factors, the best results can be accomplished by using a counterflow condenser, because in this way it is possible to discharge the condensed refrigerant with the minimum temperature difference from the entering cooling-water.

The essence of the resent invention resides in the increase 0% the heat transfer by increasing the pressure under which condensation occurs in controlled relation to the temperature of the refrigerant leaving the condenser. The im ortance of improvement in this respect will apparent from the following: i

The refrigerating eflect of one poundof carbon-dioxide expanded froma saturated pressure condition into an evaporator de- 40 creases as the temperature of the liquid increases. This is true regardless of evaporator temperature for the refrigerating effect varies only 2% (approximately) when evaporator tem rature varies from -20 F. to

+35 F. erefore, if we disregard evaporator temperature which will in practice be between the limits stated, the values will run about as follows: 4

B. T. Us for liquid at 750 pounds. B. T. Us for liquid at 850 pounds. B. T. [Pa for liquid at 965 pounds. B. T. We for liquid at 1080 pounds. 42 B. T. Us for 884 liquid at 1075 pounds. The critical temperature is 88.4".

tion pressures the refrigerating efiect is markedly increased, and the increase is even greater above than below the critical temperature. The, following are computed values 65 B. T. Us for 80 liquid at 1000 pounds."

62 B. T. Us for 85 liquid at 1100 pounds.

60 B. T. Us for 88.4 liquid at 1170 pounds.

59 B. '1. Us for from condenser at 1215 pounds.

57 B. T. Us for from condenser at 1330 pounds.

Of course, the increase in pressure entails an increased power input and an increased cooling water flow, but it is possible to develop by experiment tables as just outlined giving the super-pressure for best efiect'.

The present invention contemplates the control of condenser pressure in accordance with the temperature of refrigerant leaving the condenser. This regulation may be direct, that is, the automatic regulation may be performed in response to the temperature of the refrigerant leaving the condenser. Ordinarily, however, such an arrangement results in a structure not particularly desirable for commercial installations, and an approximately identical result can be secured by regulating according to the temperature of the cooling water leaving the condenser, or even according to the temperature of the entering cooling water.

Assuming an approximately constant. refrigerating load the temperatureof the condensed refrigerant will vary in a direct relation with the temperature of the cooling water I, a regulation in response to condenser temperature.

In the accompanying drawings several arrangements embodying automatic control are illustrated and an opportunity has been taken to show the application of the invention to systems in which the compression cycles vary slightly, thepurpose being 'to bring out the general applicability of the invention regardless of the specific details of the refrigerating cycle with which it is used.

In the drawings,-

Fig. 1 is a vertical axial section of the condenser discharge regulating valve such as ma be used inthe practice of the invention. ig. 2 is a diagrammatic view of a system including the valve of Fig. 1, showing'a simple compressor and an ordinary receiver suc tion trap.

Fig. 3 is a fragmentary view showing how the regulating valve might be included in i trolled by the temperature of the discharg- Fig. 2 in such a way as to be subject to the temperature of the discharging condensate.

Flg. 4 is'a diagram somewhat similar to Fig. 2 and showing the regulating valve coning condensing water. In this view a slight di erent system is illustrated in which the feed of liquid refrigerant to the receiver, suction trap is controlled by a float valve in an intermediate suction trap. In such a system a compressor capable of maintaining simultaneously two different suction pressures is used.

Referring first to Fig.1, 11 represents a valve body having an inlet passage 12 and a a discharge passage 13. The discharge passage leads from the bore of a valve seat bushing 14 which is threaded into a boss 15 cast integral with the body 11. The body 11 is open at its upper side, the opening being closed by a cap 16 which seats on a gasket 17 and which is held in place by machine screws 18'. The cap 16 ides a vertically movable valve stem 19 which is vertically slidable in the bushing 14 and acts as a valve therein by virtue of an axial port 21 having one or more lateral ports 22 (four being indicated). In the upper position of the stem 19 these ports 22 register with an annular groove 23 which forms a continuation of-the passage 13. As

i the valve stem 19 moves downward from its upper position the lateral ports 22 are proes'sively blanked or throttled to restrict the ow by way of 21, 22, 23 and 13. A flexible metallic bellows 24 is used at this oint to prevent leakage. The dimensions 0 the stem 19 and bellows 24 are so chosen that condenser pressure acting on the stem and bellows exercises a properly proportioned force, de-

has a shoul ered reduced end 36 enterin Supported on the body 11 are upright rods or frame members 25, conveniently four in number, which carry at their up er end a frame or yoke 26. This supports t e head 27 of a pressure motor which is the thermally responsive element of the device. This motor may assume various different forms, but is here shown as including a head 28 and metallic bellows 29 which make tight joints with I the heads 27 and 28. The head 27 has an, n

wardly projecting nipple 31 which exten a through a hole in the center of the frame member 26 and above such frame member receives a nut 32 which locks the parts in-assembled relation. The member 31 is provided with an axial port 33 which leads to a thread- -ed counterbore 34.

In the embodiments of Figs. 2 and 4, the,

passage 33 is closed by a plug threaded into 'the counterbore 34. In the embodiment of Fig. 3 the threaded counterbore 34 serves as a connection for the ressure conductin pipe,

as will hereinafter e made plain." pward movement of the head 28 is limited by a thrust member 35 carried thereby. The head 28 acts in thrust a ainst the valve stem 19 which a socket'in aportion of the head 28. A spring 37 acts in thrust between the head 28 and a seat 38. This seat may be adjusted by turning the adjusting nut 39, which is threaded on the tube 41. The tube 41 is fixed in the head 16 and surrounds the stem 19.

It-will be understood that the bellows 29 contains between the heads 27 and 28 an expansible fluid, which develops a variable pressure serving to force the stem 19 downward in a valve closing direction.

Where regulation is to be had by means of the condensing water, as in Figs. 2 and 4, the water is brought into contact with the outside of the bellows 29 by passin it through a cup or jacket in which the llows are mounted. This cup is shown at 42. It is is shown as submerged inbrine in a tank 52.

The lower end of the evaporator 51 is connected to the bottom of receiver suction trap 53 and the upper end is connected to the upper side of the receiver suction trap 53, thisbeing a familiar arrangement to maintain the evaporator 51 flooded, and to return to the III evaporator an unevaporated liquid refrigerant which may discharge from the top of the evaporator.

The suction connection 54 leads to the compressor 55 which discharges through the high ressure gas line 56 to the upper end of a ouble pipe condenser; This condenser is made up of internal water conducting pipe 57 and a surrounding pipe 58 or larger size. 19 The uncondensed high pressure gas entering by the pipe 56 flows through the interval between-the pipes 57 and 58 in counter-flow relationto the water, and the cooled or condensed refrigerant discharges from the condenser through the high pressure liquid line 59.

Pipe '59 is connected to the inlet passage 12 in the housing 11. The discharge passage 13 of the housing 11 is connected by the low pressure liquid line 61 to the receiver suction trap 53. As has been stated, the cooling water flows in counterflow relatively to the refrigerant and in the example illustrated in Fig. 2 the entering Iwater flows first through the on 42, that is, a supply pipe 62 leads throng the flexible connection 45 to the cup 42'while the other flexible connection, 44, is connected to the pipe 62 which connects with the pipe 57 at the lower end of the condenser.

a In such case the cup 42 must be closed at its top by bellows 40 if the cup is below the level of cooling water discharge. Water discharging from the pipe 57 at the upper end of the condenser, may flow to waste or be otherwise disposed of.

As explained, and as illustrated in Fig. 4, the water connections might be interchanged so that the discharging water instead of the entering water flows through the cup 42. The

pri1ne'purpose is to control the throttling action of the valve member according to condenser temperature.

,In a well designed device, and if pressure and temperature are properly coordinated, the temperature of the entering water will.

be only four or five degrees below the discharging temperature of the refrigerant leaving the condenser, so that the arrangement shown in Fig. 2 is not only simple but accurate in its action. a

If it be desired tocontrol the system directly by the temperature of the refrigerant leaving the condenser, this can be eflected in u the manner shown in Fig. 3. In this case the cup 42 is not used, and hencemay be omitted, as indicated in Fig. 3. Instead of plugging the opening 34, as shown in Fig. 2, the pipe 65 is connected to the opening 34 and termil0 nates in a bulb 66 mounted in an enlargement 67 in the high pressure condensate line 59.

v An expansible fluid is confined in the bellows 29, pipe 65 and bulb 66 and develops a pressure in response to the temperatureof the high pressure condensate, the fundamental principle of operation being identical with that shown in Fig. 2.

In Fig. 4 the evaporator 51, brine tank 52, and receiver suction trap 53 are identical with the similarly numbered parts of Fig. 2.

The section line 54 leads to the low pressure suction connection of a compressor 55*. This compressor is of a known type having two suction inlets, one of which is connected to the suction connection 54 and operates at a relatively low suction pressure. The other is connected to an intermediate suction line 71 and operates to maintain a higher or socalled intermediate suction pressure.

As an example of such a compressor may be mentioned the type having an automatic inlet valve controlling the low pressure suction to the working space, which is open throughout the suction stroke, and a higher or intermediate pressure suction which leads through the cylinder walls and is controlled by the piston in such a way as to be open only at the end of the suction stroke. The suction connection 71 leads from the top of an intermediate receiver 72. The receiver 72 is connectcd to the receiver suction trap 53 by pipe 73 and flow is controlled by a valve 74 which is actuated by a float 75. The'float 75 responds to a rise of liquid level in the receiver 72 to open the valve 74.

In the arrangement shown, the expansion of a portion of the refrigerant in the intermediate receiver 72, cools the remainder sufficiently to cause liquefaction.

- The hi h pressure gas line is identical with that in ig. 2, and is indicated by the numeral 56. The same is true of the condenser, which is numbered in the same way as in Fig. 2. The high pressure liquid line 59 leads from the lower end. of the condenser to the valve body 11, as. in Fig. 2. The low pressure liquid line 61 leads to the intermediate receiver 72 instead of leading to the receiver suction trap 53. In all cases the receiver suction trap is of suflicient volume to con:- pensate for the varying pressure in the condenser and thus it serves as a reserve storage space for the refrigerant.

In Fig. 4 as in Fi 2 the condenser cooling water passes throng the on 42, but in Fig. 4 the outflowing water. T is arrangement is shown simpl to illustrate the approximateequivalence o the two arrangements, but either arrangement may be used in Fig. 4 as in Fig. 2, or the substitute arrangement of Fig. 3 might be adopted in Fig. 4 in an obvious manner.

In-any of the cases suggested an increase v of condenser temperature or the occurrence of conditions which would produce an increase of condenser temperature for example an increase in the temperature of the cooling water, in Fig. 2) willhave the'efiect'of pro-v ducing an increase of condenser pressure. The effect .is automatically to increase the valve to close the same progressively as the' heat transfer and consequently to neutralize at least partially the loss of refrigerative effect incident to the higher temperature of the refrigerant leaving the condenser.

By adopting a proper relation between the pressures acting downward through bellows 29 and upward through bellows 24, it is possible to establish regulative characteristics are intended to be illustrative andnot limiting, and that other known circuits might be used. Furthermore, as explained, while the invention is primarily intended for use with carbon-dioxide, it is useful with any refrigerant under conditions of use requiring condensation near the critical temperature, and particularly in cases where the critical temperature may be at times exceeded.

What is claimed is,-

' 1. The combination with a refrigerating system of the compressor condenser expanded type, of a valve for throttling the outflow from the condenser; means for passing cooling fluid in heat exchanging relation with the condenser; and thermally responsive motor means subject directly-to the temperature of the cooling fluid leaving the condenser and operatively connected with said temperature of the cooling fluid rises and so arranged that the valve is normally open and commences to close as the refrigerant leaving the condenser approaches its critical temperature.

2. The combination with a refrigerating system of the compressor, condenser expander type, of a valve for throttling the outflow of refrigerant from said condenser; an expansible chamber motor operatively con neoted with said valve; means for passing condenser cooling fluid in heat exchanging relation with said motor; and an expansible fluid in said motor whose characteristics are such relatively to similar characteristics of the refrigerant that when the condensate approaches the critical'temperature of the refrigerant said valve will commence to move in a closing direction.

3. The combination with a refrigerating system of the compressor condenser expander type, using a refrigerant whose critical temperatureis at times approached and exceeded by the temperature in the condenser,of a valve for throttling the outflow from theoon denser; motor means for actuating said valve comprising a thermally responsive element operating in accordance with the temperature of refrigerant discharging from the con denser, arranged to move said valve in a clos ing direction and operative at temperatures ranging from slightly below to above the critical temperature of the refrigerant; and a pressure motor of smaller effective area than said thermally responsive motor means subject to condenser pressure arranged to urge said valve in an opening direction.

4. The combination of a refrigerating system of the com ressor condenser expander type, using a re rigerant whose critical temperature is at times approached and exceeded by the temperature in the condenser, of a valve for throttling the outflow :of refrigerant from said condenser; an expansible chamber motor operatively connected with said valve, said motor containing a thermally expansible fluid and being in heat conducting relation with the outflowing refrigerant; and a. pressure motor of smaller effective area than, and. acting in opposition to the first denser. pressure.

. system of the compressor condenser expander type, using-a refrigerant whose critical temperature is at times exceeded by the temperature in the condenser, of a valve for throttling the outflow from the condenser; and thermal ly responsive motor means operative at temperatures at and above the critical temperature of said refrigerantand connected to actuate said valve, said connection being such that as temperature in the condenser ap-' proaches and rises above the critical the valve is moved in a closing direction to retain in the condenser a pressure which rises faster than condenser mally rise. v v

6. The combination with are'frigerating system of the compressor condenser expander type, of a valve for. throttling the'outflow" from the condenser; means for pasing cooling named pressure motor and subject to conpressures would norfluid in heat exchanging relation with the condenser; andthermally responsive motor means subject directly to the temperature of the cooling fluid approaching'the condenser and operatively connected with said valve to close thesame progressively, as the temperature of the cooling fluid rises, the parts being so arranged that the valve is normally open and moves toward closed position as the. refrigerant leaving the condenser rises in temperature, the range of such rise being near to and above the'critical. H

7. The combination with a refrigerating system of the compressor condenser expander type, the condenser beingliquid cooled and the refrigerant being such that its critical temperature is at times approached 'or exceeded by the temperature of such cooling liquid,

of a valve for throttling the outflow from the condenser; motor means for. actuating said valve comprising a thermally responsive element subject to the temperature of said cooling liquid and arranged to move said valve in a closing direction as the temperature of the cooling liquid rises; and a pressure motor subject to condenser pressure, arranged to 9 urge said valve in an opening direction, said thermally responsive motor means and the flow of cooling fluid being so coordinated that the motor starts to'move said valve in a closing direction when refrigerant discharging 5 from said condenser approaches itscritical temperature.

8. The combination witha' refrigeratin system using a refrigerant whose critica perature in the condenser, of a valve for throttling the outflow of refrigerant 'from the condenser; and a thermally responsive motor operative in a temperature range, commencing below and extending above the p critical temperature, said motor being consystem, using a refrigerant whose critical temperature is at times exceeded by the temperature in the condenser, of a valve for throttling the outflow of refrigerant from the condenser; means. for passing a cooling fluid -in heat-exchanging relation with said condenser; and a thermally responsive motor 40 subject directly to the temperature of'\such cooling fluid, and connected .to close gsaid valve as the temperature of the motor ises,

said connection being such with reference to the 'diflerential between condenser temperatureand cooling'fluid temperature that as temperature in the vcondensefapproaehes the critical the valve is moved in a closing direction to retain in the condenser a pressure which rises faster than normal condenser pressure would rise.

10. The method of operating a refrigerat ing system of. the type including a condenser inv which the critical temperature of the refrigerant used is at times exceeded, which method comprises developing a secondary pressure as a result of the rise of condenser temperature is at times exceeded by the tem-' ing system of the t e including a condenser m w ich the critica temperature of the refrigera'nt used is at times exceeded, which method consists in developing by thermodynamic means, a secondary pressure in accordance with condenser temperature and in the operative range from and above the critical temperature, regulating condenser pressure in response to the secondary pressure so developed, the regulation being such that as condenser temperature approaches and rises above the critical value, condenser pressure will rise at an abnormally rapid rate. I

12. The method of operating a refrigerating system including a condenser in which the refrigerant at times exceeds the crlt cal temperature, which consists in developing thermo-dynamically a pressure which varies in response to variations of condenser temperature, and. 1n the operative range of the condenser, above the critical temperature,

applying the pressure so developed, together with partial opposition by condenser pressure to exercise a throttlin control on the condenser, the regulation belng such that as condenser temperature rises above the critical point, condenser pressure rises at an abnormally rapid rate. ,7

In testimony whereofI. have signed my name tothis specification.

, JOHN G. BERGDOLL.

temperature in the ranges commencing subner that as condenser temperature rises above 7 the critical, condenser pressure will increase at an abnormally. rapid rate. i

11. The method of operating a refrigerat- 

